Collapse Assessment of Steel Moment Frames Based on E-Defense Full-Scale Shake Table Collapse Tests

Abstract

This paper presents key parameters that affect numerical modeling of steel frame structures for reliable collapse simulations. The collapse assessment is based on experimental data obtained from a full-scale shaking table collapse test of a 4-story steel moment frame and a blind numerical analysis contest that was organized in parallel with the collapse test. It is shown that (1) there is no clear advantage between three-dimensional (3D) and 2D analyses in the prediction of a sidesway collapse mechanism for buildings with a regular plan view as in the case of study; (2) the assumption of Rayleigh damping leads to better predictions of structural response compared with stiffness proportional damping; and (3) accurate prediction of collapse necessitates that P-Δ effects always be considered in the analysis. It is also proven that accurate simulation of steel component deterioration is a key factor for reliable prediction of collapse behavior. On the basis of a synthesis of experimental and analytical studies, a few collapse mitigation alternatives are investigated. In particular, the effects of the strong-column/weak-beam ratio and exposed base plates on the collapse capacity are assessed. It is notable that a combination of bending strength increase and delay of local buckling in first-story columns is most effective for the enhancement of seismic performance against collapse.